While perhaps the most common refrain about cannabis research is that more is needed, research has been rising, and maturing, in recent years.
Still, the placement of cannabis in the strictest category of the federal Controlled Substances Act, Schedule 1, for the past fifty years has meant that researchers have needed to jump through more hurdles than if they were investigating other materials. Further, there has been a lag in the establishment of agreed upon national standards, for example, what counts as a “dose” of cannabis — until now.
Late last week, the National Institute on Drug Abuse published a notice to researchers that, as of May 7, the “standard THC unit is defined as any formulation of cannabis plant material or extract that contains 5 milligrams of THC.” This standard dose mainly applies to researchers applying to study THC, rather than other cannabinoids.
“Inconsistency in the measurement and reporting of THC exposure has been a major limitation in studies of cannabis use, making it difficult to compare findings among studies,” the notice read. “A standardized measure of THC in cannabis products is necessary to advance research by providing greater comparability across studies of both its adverse effects and potential medical uses.”
NIDA also published a Q&A on the topic.
The standard unit has been in the works for some time. Nora Volkow, director of NIDA, told members of Congress that NIDA was creating a “unit” of cannabis that can be used for consistency across research during a January 2020 House Energy and Commerce Subcommittee on Health hearing on the state of cannabis research, for which she was asked to testify about research, for example, related to cannabis use by pregnant people, and youth use.
“Past research has been important, but has limitations. And as a result of that, there has been a lot of questioning of the results that have emerged from that research. And we want to change that, such that the future studies can not be criticized for the lack of rigor in quantifying the level of exposure,” Volkow told Cannabis Wire on Monday.
The standard THC dose is a “first step” in increasing that research-related rigor, Volkow said.
“If you look at the literature, all of the studies that have been reporting on negative effects or lack of negative effects from consumption of marijuana have not actually documented the doses of exposure,” Volkow said. “It’s very different to consume, say for example, 50 milligrams of THC than to have an exposure of five milligrams. And yet none of this has been controlled by the studies and it hasn’t been controlled because there has not been agreed standardization of how to report that. And we want to change that. That’s why we’re bringing forward the standard dose so that we can start to develop information and knowledge as well as guidelines on how to apply it.”
For the past year, Volkow said, NIDA has been having conversations with researchers to “get their input in terms of what they thought was what a reasonable standard dose.” Their input is critical, Volkow said, “because otherwise it would not be adopted by the research community.”
Volkow added that “having a standard dose will be extremely important for any work that it aims to investigate potential medical benefits from marijuana.”
Cannabis is now legal for adult use in 18 states, and most states have some sort of medical cannabis law. Even with all of that activity, Volkow said one of the factors behind why it has “taken so long to finally say ‘guys, let’s go, let’s go and get a standard dose,’ is the effects are likely very different” depending on mode of consumption, meaning that there’s a consideration, from a research perspective, of whether someone is smoking cannabis, or ingesting it through a “brownie or candy.”
Also, researchers weren’t set on what the specific standard dose should be, which “generated controversy,” Volkow said. This disagreement is also true among state lawmakers and regulators: While many states, for example, limit an edible serving to 5 milligrams of THC, this is not uniform from coast to coast.
The two proposed doses were 5 milligrams of THC and 10, Volkow said.
“Those that were proposing the 10 milligram dose of THC were arguing that a 5 milligram dose is very low, whereas those that were proposing a 5 milligrams were saying ‘no, a 5 milligram dose of THC, actually, for someone that is not a regular user, can have pretty strong pharmacological effects,’” Volkow said.
What about CBD, which now appears on shelves nationwide, from mall kiosks to New York City bodegas to Bed Bath & Beyond?
“There hasn’t been the urgency of doing it for CBD because, overall, CBD is not addictive. Overall, CBD does not produce the toxicity,” Volkow said, adding the caveat that in very high doses, CBD can cause liver issues. “It’s a pretty safe substance. And the trials that have been ongoing, for example, like pharmaceuticals, have delineated very specifically the doses of which the products are therapeutically beneficial, as is the case for the approval of cannabidiol for the treatment of epilepsy. So the urgency is not there as there is for THC.”
What’s next? Volkow said she and NIDA will continue to share information with the scientific community about the 5 milligram dose of THC, both in the United States and abroad.
“There’s a lot of educational work that will be required, but we have to start someplace,” Volkow told Cannabis Wire.
